1. Field of the Invention
The present invention relates to a substrate processing apparatus and a substrate processing method, and in particular to a substrate processing apparatus that subjects a substrate housed in a processing chamber to plasma processing.
2. Description of the Related Art
Substrate processing apparatuses that subject a wafer as a substrate to plasma processing such as etching processing have a processing chamber (hereinafter referred to as the “chamber”) that houses a wafer and can be evacuated, and a mounting stage (hereinafter referred to as the “susceptor”) on which the wafer is mounted during the etching processing. In the evacuated chamber, plasma is produced, and the wafer is etched by the plasma. The susceptor has a temperature control mechanism to control the temperature of the wafer.
In the susceptor, an annular focus ring made of, for example, silicon is provided so as to surround a peripheral portion of the mounted wafer. The focus ring focuses plasma in the chamber onto the wafer.
When the wafer is subjected to the plasma processing, the temperature of the wafer rises because it is exposed to heat from the plasma, and hence the temperature control mechanism of the susceptor cools the wafer so as to maintain the temperature of the wafer constant, thus improving the uniformity of the plasma processing (see, for example, Japanese Laid-Open Patent Publication (Kokai) No. 2004-193567).
However, in the conventional substrate processing apparatuses described above, temperature management is not carried out for an in-chamber component such as the focus ring located in the vicinity of the plasma, and hence heat transfers between the focus ring and the plasma, and also, heat transfers between the peripheral portion of the wafer and the focus ring. As a result, the state of the plasma changes, and the state of the plasma on the wafer becomes unstable.
Generally, in substrate processing apparatuses, the uniformity of plasma processing carried out on a wafer can be improved by maintaining plasma on the wafer in a desired state and maintaining the processing temperature of the wafer uniform over the surface thereof. It is thus impossible for the conventional substrate processing apparatuses to improve the uniformity of the plasma processing carried out on a wafer.